Add Windows support to libwg

2 files changed, 141 insertions, 0 deletions

diff --git a/wireguard-go-rs/libwg/README.md b/wireguard-go-rs/libwg/README.md
index 39ad48e3e0..e5b96928f7 100644
--- a/wireguard-go-rs/libwg/README.md
+++ b/wireguard-go-rs/libwg/README.md
@@ -7,6 +7,7 @@ It currently offers support for the following platforms:
 - Linux
 - macOS
 - Android
+- Windows
 
 # Organization
 
@@ -16,6 +17,8 @@ It currently offers support for the following platforms:
 
 `libwg_android.go` has code specifically for Android.
 
+`libwg_windows.go` has code specifically for Windows.
+
 # Usage
 
 Call `wgTurnOn` to create and activate a tunnel. The prototype is different on different platforms, see the code for details.
diff --git a/wireguard-go-rs/libwg/libwg_windows.go b/wireguard-go-rs/libwg/libwg_windows.go
new file mode 100644
index 0000000000..f4ad7faa6d
--- /dev/null
+++ b/wireguard-go-rs/libwg/libwg_windows.go
@@ -0,0 +1,138 @@
+/* SPDX-License-Identifier: Apache-2.0
+ *
+ * Copyright (C) 2017-2019 Jason A. Donenfeld <Jason@zx2c4.com>. All Rights Reserved.
+ * Copyright (C) 2024 Mullvad VPN AB. All Rights Reserved.
+ */
+
+package main
+
+// #include <stdlib.h>
+// #include <stdint.h>
+import "C"
+
+import (
+	"bufio"
+	"strings"
+	"unsafe"
+
+	"golang.org/x/sys/windows"
+
+	"golang.zx2c4.com/wireguard/conn"
+	"golang.zx2c4.com/wireguard/device"
+	"golang.zx2c4.com/wireguard/tun"
+
+	"github.com/mullvad/mullvadvpn-app/wireguard/libwg/logging"
+	"github.com/mullvad/mullvadvpn-app/wireguard/libwg/tunnelcontainer"
+)
+
+// Redefined here because otherwise the compiler doesn't realize it's a type alias for a type that's safe to export.
+// Taken from the contained logging package.
+type LogSink = unsafe.Pointer
+type LogContext = C.uint64_t
+
+//export wgTurnOn
+func wgTurnOn(cIfaceName *C.char, cIfaceNameOut **C.char, cLuidOut *C.uint64_t, mtu C.uint16_t, cSettings *C.char, logSink LogSink, logContext LogContext) C.int32_t {
+	logger := logging.NewLogger(logSink, logging.LogContext(logContext))
+	if cIfaceNameOut != nil {
+		*cIfaceNameOut = nil
+	}
+
+	if cIfaceName == nil {
+		logger.Errorf("cIfaceName is null\n")
+		return ERROR_GENERAL_FAILURE
+	}
+
+	if cSettings == nil {
+		logger.Errorf("cSettings is null\n")
+		return ERROR_GENERAL_FAILURE
+	}
+
+	settings := C.GoString(cSettings)
+	ifaceName := C.GoString(cIfaceName)
+
+	// {AFE43773-E1F8-4EBB-8536-576AB86AFE9A}
+	networkId := windows.GUID{
+		Data1: 0xafe43773,
+		Data2: 0xe1f8,
+		Data3: 0x4ebb,
+		Data4: [8]byte{0x85, 0x36, 0x57, 0x6a, 0xb8, 0x6a, 0xfe, 0x9a},
+	}
+
+	tun.WintunTunnelType = "Mullvad"
+
+	wintun, err := tun.CreateTUNWithRequestedGUID(ifaceName, &networkId, mtu)
+	if err != nil {
+		logger.Errorf("Failed to create tunnel\n")
+		logger.Errorf("%s\n", err)
+		return ERROR_INTERMITTENT_FAILURE
+	}
+
+	nativeTun := wintun.(*tun.NativeTun)
+
+	actualInterfaceName, err := nativeTun.Name()
+	if err != nil {
+		nativeTun.Close()
+		logger.Errorf("Failed to determine name of wintun adapter\n")
+		return ERROR_GENERAL_FAILURE
+	}
+	if actualInterfaceName != ifaceName {
+		// WireGuard picked a different name for the adapter than the one we expected.
+		// This indicates there is already an adapter with the name we intended to use.
+		logger.Verbosef("Failed to create adapter with specific name\n")
+	}
+
+	device := device.NewDevice(wintun, conn.NewDefaultBind(), logger)
+
+	setError := device.IpcSetOperation(bufio.NewReader(strings.NewReader(settings)))
+	if setError != nil {
+		logger.Errorf("Failed to set device configuration\n")
+		logger.Errorf("%s\n", setError)
+		device.Close()
+		return ERROR_GENERAL_FAILURE
+	}
+
+	device.Up()
+
+	context := tunnelcontainer.Context{
+		Device: device,
+		Logger: logger,
+	}
+
+	handle, err := tunnels.Insert(context)
+	if err != nil {
+		logger.Errorf("%s\n", err)
+		device.Close()
+		return ERROR_GENERAL_FAILURE
+	}
+
+	if cIfaceNameOut != nil {
+		*cIfaceNameOut = C.CString(actualInterfaceName)
+	}
+	if cLuidOut != nil {
+		*cLuidOut = nativeTun.LUID()
+	}
+
+	return C.int32_t(handle)
+}
+
+//export wgRebindTunnelSocket
+func wgRebindTunnelSocket(family uint16, interfaceIndex uint32) {
+	tunnels.ForEach(func(tunnel tunnelcontainer.Context) {
+		blackhole := (interfaceIndex == 0)
+		bind := tunnel.Device.Bind().(conn.BindSocketToInterface)
+
+		if family == windows.AF_INET {
+			tunnel.Logger.Verbosef("Binding v4 socket to interface %d (blackhole=%v)\n", interfaceIndex, blackhole)
+			err := bind.BindSocketToInterface4(interfaceIndex, blackhole)
+			if err != nil {
+				tunnel.Logger.Verbosef("%s\n", err)
+			}
+		} else if family == windows.AF_INET6 {
+			tunnel.Logger.Verbosef("Binding v6 socket to interface %d (blackhole=%v)\n", interfaceIndex, blackhole)
+			err := bind.BindSocketToInterface6(interfaceIndex, blackhole)
+			if err != nil {
+				tunnel.Logger.Verbosef("%s\n", err)
+			}
+		}
+	})
+}